Rotary tin plate shears



Jan. 7, 1941., w. w. MAGFARREN ROTARY TIN PLATE SHEARS INVENTQR.

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Jan. 7, 1941.

W. W. MACFARREN ROTARY TIN PLATE sHEARs Filed June 2, 1936 5Sheets-Sheet 2 om mn wa mm MQ @ma /mz/W 5 Sheets-Sheet 3 Filed June 'l2.. 193s i 1122.122212 :III: Yi

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Jan. 7, 1941.

W, W. MACFARREN ROTARY TIN PLATE sHEArvfs Filad June 2, 1936 5Sheets-Sheet 4 Patented Jan. 7, `11.941

UNITED STATES PATENT OFFICE ROTARY TIN PLATE SHEABS Walter W. Macfarren,Los Angeles, Calif. Application June 2, 1936, Serial No. 83,174

15 Claims. (Cl. 164-68) My invention relates to rotary shears, and maybe used for the automaticA shearing of any material in the form of thinsheets, webs. or strips, as for instance, paper, card board, brass,aluminum,

or steel. The present invention is specifically designed for theshearing of rolled steel tin plate stock, or tin plate, from coils.

The machine is designed to shear strip steel from 12" to 32" in width,and of gauges from i0 .007" to .015", and to cut therefrom sections ofany fractional lengths between the limits of 12" and 48", and varying byas little as .005".

The speed of operation may be varied from 100 ft..per minute (feed) orless, to 2000 ft. per minute, or more, depending on the length of thecut sections, as will hereinafter appear.

In previously issued patents for rotary ilying shears, I have shownmachines designed to operate with the peripheral speed of the knivessubstantially equal to the linear speed 'of the strip being cut.This'isy synchronous operation.

In Patent No. 1,994,107, I have shown special electrical and mechanicalcontrols for synchro,- nizing the above named speeds. In various otherco-pending applications, particularly Ser. No. '73,790 andvSer. No.96,501 I have shown rotary shears using various degrees of asynchronism,or -unequal speeds between the knives and the strip,

to a limited degree.

Inthe present invention, due to the thin material to be operated on, andits light weight and flexibility, I make us/e of this asynchronous meth-Vod to a considerable degree. 'I'he present invention also makes use ofa loop" between the primary and the secondary feeding means, in a manner similar to my co-pending application Ser. No. 96,501, except thathere the primary feeding means is a leveller. The present invention alsomakes use of pinch rolls of varying radius for varying the feed of thematerial, in a manner similar to those shown in my co-pendingapplication Ser. N0. 96,501.

The present invention also makesl use of multiple shear knives as shownin my co-pending ap- 45 plication Ser. No. '13,790 but in this case theknives are all rigidly mounted on the shear drums, and used in a novelmanner to cut Vsections of diiiere'nt lengths as will appear later. Inthe drawings,

Fig. l is an end elevation of the shear proper.

Fig. 2 is a plan view of the same partly in section, and with the upperportion omitted.

Fig. 3 is an elevation, partly in section, of the receiving side of themachine.

55 Fig. 4 is adiagramA showing the coll, the leveller, the loop, thepinch rolls, the shear drums,

v and the receiving and discharge conveyors.

Fig. 5 is an venlarged vertical section through the 'pinch rolls and theknife drums. 5

Fig. 6 is a diagram of. the drive for the discharge rollers. i

Fig. 'l is an end view of a special knife gauge, and

Fig. 8 is a table or data sheet showing the various cuts, speeds, feeds,gears, et cetera. 'lo For a preliminary general survey, referring toFig. 4, the strip 2 is drawn from the coil i by the leveller 3, whichmay be of any usual construction, and which should be driven by its ownvariable speed motor. The guides or chutes 4 extend l in a reversedcurve from the last leveller rollv to the lower end of a belt conveyor5, comprising the upper 4pulley 5, the lower pulley 1, the intermediateidler pulleys 8.. and the belt 9.

The pinch rolls Ill are adjacent to the pulley go t, and the shear drumsI5 and 20 carry the cutting knives 40. '111e cut sections are dischargedby the knives onto the small rollers 2l. and from thence pass on to aconveying belt 25. The belt conveyor 5 is preferably driven from theleveller l, and the operation will be described in more detail later.

The base of the machine is a bed plate i8, upon which are mounted twohousings 30 and 35, which are secured to the bed plate is by root nousls. 3

Each of the housings 30 and 35 is provided with accurately aligned upperand lower bores 22, in which are mounted the main roller bearings 23 forthe knife drums I5 and 20.

The housings 30 and 35 are of the general form 35 of an elongated 0 andhave nobearing boxes, the bearings 23 being rigidly mounted directly inthe bores 22. This construction is rigid, economical, and accurate.

The knife ydrums i5 and 2li may be duplicates 0 except as to length andare preferably made of forged steel with integral trunnions, andaccurately machined all over. Both drums l5 and 20 are provided withextensions 26 to carry the connecting gears 2l, which maf have straightspur teeth as shown, or may be of the construction shown in mycov-pending application Ser. No. 73,790 with double helical teethandspecial means for eliminating backlash.

The gears 21 are each keyed to their drums, 50 and clamped by a nut 28against a spacer 29, as shown. Outside the nut 28 on the upper drum I5,there is mounted a pulley y wheel 3| to be driven by a belt.

For the speciiic design of machine illustrated in the table Fig. 8, twopairs of cutting knives are used, both pairs being used when cuttingsections from 12" to 24" long, and only one pair being used when cuttingsections from 24" to 48" long.

It is obvious however, that for a larger machine, or even for the designshown, four pairs of knives might be used to advantage, and in Fig. 5 Ihave so shown it. For vthe present ma-V chine, the use of four pairs ofknives would enable the machine to cut sections synchronously down to 9"long, and asynchronously down to 6" long.

For a machine of say twice the size, and having four pairs of knives,sections could be cut from one foot to eight feet long, using theprinciples of action herein described. In Fig. 5 the diameter of theknives from tip to tip is 11% (the gears 21 having the same pitchdiameter). The knife periphery is therefore 36.14", butin the table Fig.8 I have used an even three feet.

Each knife 46 is mounted in a milled slot 32, these various slots beingexactly parallel to the drum axis both radially and longitudinally. The

knives 46 are made of hardened steel and ground on both sides 33 and 34,and on both edges 36 and 31 (Fig. 7).

'I'he edges 36 and 31' are oppositely beveled as shown, an amountsuicient to keep them within the circle described by their cuttingAedges (or corners). The slots 32 are slightly wider than the knives 46,so the latter will enter easily. The cutting side 33 of the knives 46 isalways set against the working side 38 of the slots 32, so that if theslots are accurately formed, as they must be, the cutting edge of eachknife is exactly registered with the axis of its drum.

The knives 46 are held in the slots 32 by a line of hollow set screws4|, there being 12 of these for each knife as shown in Fig. 2. These setscrews remain permanently in place, and can be tightened or loosened bya half turn. Clearance spaces 43 are milled for the set screws 4|.

The bottoms 42 of the slots 32 are bevelled to t the edges 36 and 31 ofthe knives 46, and small liners 44 are used to position the knivesradially. These liners 44 will vary in thickness to suit the variationsin knife width caused by wear and'grinding, and in Fig. 7 I have shown agauge |36 suitable for determining this thickness. This is simply a,hardened steel bar having a groove which correctly fits the assembly ofknife and liner. Knives and liners thus gauged will ilt the drumsexactly, without` adjustment, and therefore the knives may be quicklychanged, or applied.

Reverting to Fig. 2, the gears 21 are enclosed by a casing 46 secured tothe housing 35. The bearings 23 are held by retainers 41 and 48, andbronze washers 49 are secured to the ends of the drums I5 and 26, andbear against the inner retainers 41. The upper drum I5 is mounted toprevent endwise motion in its bearings, and the lower drum 26 is mountedto permit a slight motion endwise.

A variable speed Amotor 45 is mounted above the machine, and rests on apair of square tubular members or beams 56, which extend from housing 36to housing 35 .and are secured to both of them. The motor 45 ispreferably an exact duplicate of the leveller motor for reasons whichwill appear later, and has a pulley 5| which drives a belt 52 engagingthe pulley 3|. A pair of idler pulleys 53 also engage the belt 52, andare mounted on pins 55 supported by a bracket 54, which 1n turn issecured to the beams 56.

It is to be noted that in operation, the motor 45 is set by usualcontrols for a desired speed, and that the knife drums I5 and 26 rotateat a substantially constant speed at all times when cuts are being made.

The pinch rolls I6 each comprise a tubular shaft 56, a drive member 51for the. same,l two end collars 58, three intermediate spacers 59, andfour or more pneumatic rubber tires 6|. The tires 6I are of the doughnutvariety, as made for airplanes and small cars, and a size close to thesize given herein is commercially available. The shafts 56 are mountedin ball or roller bearings 62, which are held in sliding boxes 63, whichlatter are adjustable vertically in guides 64 formed in the housings 36and 35.

The boxes 63 are adjusted toward or away from each other by four screws65 and 66, in such a manner that the surfaces of the tires 6I whichcontact the strip 2 are maintained at a constant level with reference tothe knife drums I5 and 26. In other words the delivery of the strip fromthe pinch rolls is at a constant level.

There are two sliding boxes 63 for each housing 36 and 35, one for thelower and one for the upper pinch roll |6. Each box 63 has two threadedopenings or integral nuts through which the screws 65 and 66 pass, andfor each box 63 these threads are right and left hand. For the upper box63 of housing 36 (Fig. 2) the near threads are R. H. and the far threadsL. H. For the ylower box the near threads are L. H. and the far threadsR. H. 'The screws 65 and 66 are threaded to correspond. e

A pair of brackets 61 connected by ribs 66 are secured to one of thebeams 56, and beneath each bracket 61 there is secured a bearing box 12containing two helical gears 69 and a worm 1|. One of the gears 69 ismounted on each of the upper ends of the screws 65 or 66, and the worm1I engages both gears 69 and is mounted on a shaft 13 supported inbearings 14 in the boxes 12. Each gear 66 is held by a nut 16 so thatthe weight of the pinch rolls I6, and the sliding boxes 63, is hung onthe screws 65 and 66. The worm 1I and the gears 69 may be R. H. or L.H., as convenient.

The left end of the shaft 13 is supported in a bearing bracket 11mounted on the upper section of the gear box 66, and an indicator 16 isprovided, to register with graduations on the face of the hand wheel 15.By the above described mechanism, the pinch rolls I6 are moved toward oraway from each other in such a way as to change their working radii R inFig. 5.

This action results in more or less of the strip 2 being fed to theknives 46, as will be readily understood. Applicant believes that thefeeding action will be directly proportional to the radius -of the upperdrum I5, and a fourth shaft 83 directly below the shaft 62. The rightVend 0f shaft 86 is inserted in a counterbore 84 in the left trunnionyof drum I5, and keyed thereto. Its left end is supported by a bearing35. The shaft 8| is supported in bearings 66. The shaft 82 is tubularand is mounted in bearings 81. Theshaft 88 is also tubular and moimtedin bearings 88.

'I'he pinch `rolls I8 are driven from shafts 82 and 83 by spindles 88.Each spindle 88 has a small integral spur gear 19 at each end.

I'he right end of each spindle 88 `engages a driving member 51 in one ofthe-tubular shafts 58, the said member lbeing provided with internalgear teeth loosely engaging the teeth of the gear 18 on the spindle 98.'Ihe member 51 is keyed or otherwise secured to the shaft 56 to driveit. A similar drive member 88 is loosely set in the left end of eachshaft 82 and 88, and these members 89 have a square end 9| which mayengage a square hole 82 in a plate 98, secured by bolts 94 to a flange95 on each shaft 82 and 83.

By this arrangement, the spindles 88 are of ample length to give therequired vertical adjustments of the pinch rolls I8, and are concealedand out of the way. s t

The shaft 88 carries four spur gears A, C, E, and G, all loosely mounted,on the shaft, and driven bylaw clutches 86 and 91, which latter arekeyed to shaft 88 and are shifted by shifters (not shown) on thevertical shafts I8| and |82, which are in turn operated respectively bylevers |85 and |86. (Fig. 3.)

Similar clutches 88 and 88, are mounted on the hollow shaft 82, andoperated from similar vertical shafts |83 and |84.

The shaft 8| carries seven spur gears B -M- D-K-F-I-H, all keyed to theshaft. The shaft 82 carries four spur gears N-L-J-I88. Theshaft 83carries a gear I I8 of equal size to the gear |88, and which mesheswith,` and is driven thereby, so that the two shafts 82 and 88 alwaysrotate at the same speed, andl in opposite directions to drive the pinchrolls I8. v These gears have the following dimensions:

Gear No. Diam. Pitch L symbol teeth pitch diam. R'P'M Speeds Y Inches 808 10 100.00 60 8 7% 133.33 58 6 9% 100.00 47 6 7% 123. 40 57 6 9% 100.0048 6 8 118.75 54 46 `9 100.00 5l 6 8% 110.00 53 8 6% v 27 g lg 81. @-75.117-72. 20--67.0lr

1 Z9 g gig/ 102. 12b-95.2741. 70-84.94

0 70 8 8% 133.33-1Z!.40118.75-110.00 66 6 1l G6 6 11 With the sheardrums i2 and 28 assumed to run at 5100 R. P. M. the gears ACE and Grwill have the same speed, and the shaft I8| will run atl33.33-l23.i0-118.75 or 110 R. P..M., depending on which gear isdriving. The above four speeds may be transferred Idirectly to the pinchroll drive shafts 82 and 83, by means of equal 'gearsthe equal gears Mand N, and the H80 and iiil. v

The idylle primary speeds above may also be reduced ay' the gears K andr. to 102.95-952'1-9mo and 882.04 P.` M. for shafts 82 and 83. And also,these speeds may be reduced by the gears I and .l to 81.22-15.17-7228-and 67.01 R. P. M. As shown there are thus available twelve speeds forthe pinch rolls I8, varying by gradual steps from 67.01 to 133.33 R. P.M.

As shown bythe table Fig. 8, the differences motor.

in these speeds from step to step are covered ^by the variations in' theworking radius R of the pinch rolls I8, so that in effect, any speed maybe had between 67.01 and 133.33 R. P. M. Or, in other ywords, thecorrect rate of feed for the strip 2 may be obtained to cut sectionsfrom 12" to 48" long, -as shown by the table.

At the delivery side of the machine I provide a pair of brackets III and||2 secured respectively to the housings 38 and 35, and which may beconnected by integral ribs H3, as indicated in dotted lines in Fig..1.The brackets III and II2 carry the shaft Ill and its pulley IIS. Theyalso carry the small discharge rollers 2|, and the driving rollers ||6therefore, and one end of the shaft |28. V

Thedrlving rollers I I6 are short-about 4" face (see Fig. 2) and areprovided with rubber rings or sheaths II1, which bear against the smallrollers 2| and drive them. 'I'he rollers II6 are in turn driven by apair of rollers I|8 on the shaft |28, the same having rubber sheathsIIS,

- which bear against and drive the covers ||1 of rollers H8.

The shaft I 28 passes through the housing 38, and carries a smallsprocket |2| at its left end (Fig. 2), which may be driven from a.sprocket 'I per minute when the knife drums I5 and 28 rotate at 180 R.P. M., in order to insure a free discharge of the cut sections. 1

'I'he belt conveyor 25 is similar to the one covered by my cci-pendingapplication Ser. No. 96,501 and may be driven from its delivery end, orfrom a point between its This conveyor may be operated in threedifferent ways, as follows: l

1. At the same speed as the delivery rollers 2|, which will deliver thecut sections side by side, without overlap. 'I'his is not advised.

2. At a slow uniform speed, say 1A to l/l" advance for each section cutfrom the strip, which will deliveru the sections overlapping.

3. With alternate stops and starts. During the new coil is being set inplace (or at other times), the conveyor belt 25 can be advanced enoughto leave room for a new pile, or the pile just formed can be. movedto a:desired point. This is the preferred method.

At 823 in Fig. 3 I have shown an oil pump which may bevdriven by gears|24 from the shaft 83 to pump oil to a reservoir |25, resting on thebeams 58, andfrom which gravity oil feeds may be led to all pointsrequiring lubrication.

Referring to the table Fig. 8, column 1 shows the lengths of the cutsections by inch steps, col. 2 shows the distance travelled(circumferentially) by the knives during the intervalsfgbetween cuts, orper cut, co1. 3 shows whether one or two pairs of knives are in use,col. 4 shows the asynchronous travel of the strip in inches or theamount the strip travels less (minus), or

ends by a separate stops the sections will form a pile, and when a perminute, at these. speeds, col. 9 shows the gears in use to give thepinch rolls the proper speed for the section lengths vbeing cut. col. 10showsthe corrp nding R.. P. M. of the pinch rolls, col. 11 shows theadvance of the strip to the knives in feet per minute, col. 12 showswhether the knives exert ai pull or a check on the passing strip, col.13 shows the amount of this pull or check in thousandths of an inch, andcol. 14 shows the eective diameter of the pinch rolls, or twice theworking radius R of Fig. 5. The diameter is used as being easier tovisualize.

Especial attention is directed to columns 12, 13, and 14, which show theguiding principles of the present invention. It is obvious that for aheavy rotary shear cutting heavy strip steel at high speeds, the stripspeed and the knife speed should be substantially the same at theinstant of cutting. If this is not so the cutting (feeding) speed mustbe reduced considerably. Generally speaking, asynchronism is bad. It isalso obvious that for thin light sections, some degree ofasynchronism-may be successfully used, even at high speeds, but thetable Fig. 8 is the iirst time these conditions have been expressed inreadily understandable figures, as far as applicant knows.

A machine designer can get more information from this table in a shorttime than he can obtain from pages of description.

In order to obtain the data in cols. 13 and 14, the following constantsfor this machine (as previously assumed) are used.

The maximum thickness to be cut is .015" (gauge). Assuming the cut iscompleted when the knives are at the vertical center line of the drumsl5 and 20 as indicated in Fig. 5, the cutting angle, or the anglebetween the vertical center line and a radius drawn to the point wherethe knivesiirst grip the strip (when .015" apart) may be computed fromthe known thickness, and the known knife radius.

For .015" gauge and 5%" knife radius, the cutting angle is threedegrees. The cutting chord, or the distance from the point of knife gripto the vertical center line is .30". The retarding chord (check) isdouble this, or .60" as the knives must open .015" after the cut ismade, to let the strip pass on.

Now it will be evident that with synchronous knife and strip speeds,there will be neither a pull nor a check Such conditions are shown inthe table Fig. 8 for 10" and 36" cut sections. And also, for a minusasynchronism, that is, the

strip moving at a lesser speed than the knives, a

pull will beproduced. The amount of this pull will be the constantcutting chord of .30" multiplied by the percentage of asynchronism. Fora 12" cut this is .30X331/3% or .10".

Similarly for a plus asynchronism, the amount of the check will be theretarding chord of .60" multiplied by the percentage of asynchronism.For a 48" cut this is .60X331/3% or .20".

From this it will be seen that the percentage of asynchronism determinesthe maximum speed at which the shear may be successfully operated, whichis just another way of repeating that these speeds should not be too farapart. However, a percentage, of asynchronism which would be im'-possible, or very undesirable on thicker material, may be freely andsuccessfully used on such light -material as is now under discussion,because the cutting angle, and the cutting and retarding chords increaserapidly with increase in thickness.

Regarding speeds, there is no apparent reason why, a shear of thisdesign, cutting sheet steel of .015 gauge, will not operate smoothly at2000 feet per minute when making synchronous cuts. as 18" or 36". For a15" cut the pull is only .05", and for a 2l" cut the check is only .10".Similarly, for a 30" cut the pull is only .05, and for a 42" cut thecheck is only .10".

It is probable then, that sections'from 15" to 21" inclusive, and from30" to 42" inclusive, may be cut almost as fast as for synchronous cuts.It is also probable that the other cuts tabluated which are outside thisrange, may have to be made at somewhat lower speeds, but for .015 gaugeapplicant believes a minimum speed `of 1000 feet per minute can besuccessfully used throughout the range of the table Fig. 8, of from 12to 48".

AS shown in Figs. 1, 3, and 5 the path of the strip 2 between the Vpinchrolls I0 is at a level a little above the path of the strip between theknives 40. This setting is purposely made to constrain the strip 2 totravel in a slight reverse curve or non-rectilinear path between thesepoints. When a pul1" occurs this reverse curve is straightened somewhat,and also the amount of play or torsional looseness between the drivingends of thespindles and the members 51 and 8S, is purposely made suchthat the periphery of the pinch rolls I0 may be freely advanced by thepull on the strip, without affecting any other parts. The amount of thisplay should be at least $41".

It is to be noted that the amount of the pull given in the table Fig. 8,column 13, will never be fullyrealized, because the strip will separatewhen cut about the way through, and this action will be assisted by thepull. While the check is double -the amount of the "pul1 for the samepercentage of asynchronism, its effect" is practically negligible forthin material, as the strip 2 will merely bend or bow a small amount totake up the extra length. This bending action will be assisted andassured by the curved path of the strip between the pinch rolls andtheknives, as previously described.

However, `for a larger machine of the same type, and one to cut thickermaterial, I prefer to use la curved guide or guides, as indicated indotted lines at |26 in Fig. 5. The upper curved surfaces of these guidesconstrain the strip 2 to take a slight initial bend before the cutoccurs; and during the out, if a "checking" cut, this bend is merelyincreased to an amount sufficient to absorb the check.

Reverting now to Fig. 4, the koperation is as xfollows, assuming thevspeeds of the leveller and the shear to have been previously adjustedto a desired relation. The shear runs at as near to a constant (set)speed as its motor 45 will drive it, and the pinch rolls I0 run at anequally constant but different speed determined by the selective gearsA-B-(B, etc.

The leveller 3 being in motion, the end of a coil of strip 2 is fed toit, and this end passes out and slides down the curved guid 4 until itis engaged by the belt 9, which carries it uphill and between the usualadjustable side guards- |21 to the pinch rolls I0. i ,A

At this time the roller is depressed and the circuit controlled by itthrough wires |28 and |29 is closed. This circuit leads to the armatureof the leveller motor,.and includes enough resistance to cut down theset speed of the leveller motor from 3% to 5%.

When the pinch rolls I0 engage the strip 2, it

is fed to theknives and cut, and the loop I 3 in the strip 2 graduallyrises to its lower level Il, and then to its normal or average level I3, and

iinally to its high position I2, at which point or a' little above it,thI roller II is raised, the aforesaid resistance is t out, and theleveller motor speeds up to normal speed to drop the loop.

'Ihe loop I3 is thus automatically maintained by these slight changes inspeed oi the leveller motor. In this connection, this loop could bedispensed with by the use of the special synchronizing controls coveredby my Patent 1,994,107, but for a small machine I prefer the arrangementherein shown.

It will be noted that the power required by the leveller and by theshear is so small and so nearly equal that their motors may beduplicates. It is further evident that the same branch mains couldsupply both motors. Therefore the variations in line voltage would bethe same, and would aiect both motors alike, and as' the loads on bothmachines are practically uniform (due to shear iiy wheel 3l), these twomotors could probably be' made to run at speeds within 3% of each other,by the usual field resistances.

At the higher operating speeds it might be necessary or desirable toslow down both .the leveller vand ,the shearwhile a new strip wasentering the pinch rolls. For this purpose a joint control ofthe twomotors could be used.

It .will be understood that very fine adjustments as to the lengths ofthe cut sections may be obtained by manipulation of .the hand wheel tilt15, which controls the working radii R of the pinch rolls. It lis ofcourse evident that any lengths of cut sections between the inch lengthsshown in .the table Fig. 8 may be obtained in this way, and it will bealso evident that if the pinch rolls I 0, at the start of a tabledivision,

as say 35'K', are too large to make an intermediate cutfof say 35%", thenext geared speed can be used, as for a 36, cut, and .the workingdiameter of the pinch rolls reduced `from 11.13" to the dimensionnecessary. As previously shown, additional geared speeds may be easilyincorporated in the design. v

In regard to the durability of the pneumatic tires 0i on the pin'chrolls I0, 1000 feet per minute feed of the strip 2 is equal to 11.4miles per hour. At .this speed, and for the light duty required, thetires 0I should give 20,000 miles of service, which is equal to 1754hours, or 220 -hour days, or about a years service, as it is notprobable the shear could be kept in constant operation at this speed.The foregoing description` is believed` to fully cover the presentinvention, and to show .that a machine constructed in accordancetherewith is comparatively simple, and may i very accurate, reliable,and durable. Where sizesdimensions, gear ratios, or other similar dataare given, it will be understood that such data is assumed, and givenfor illustrative illlliwses only, and is subject to wide variation tomeet the conditions imposed by any speciiic design.

i claim as my invention:

i.` In a rotary shear for making transverse cuts on moving materialin-'rthe form of a strip, a pair of equal diameter rotary knife carryingdrums mounted on'xed centers and geared together, cutting mives carriedthereby, means for feeding the strip .to the knives, means to drive ltheyieeding means to feed the stripv synchronously to the mecd of theknites, and other means to drive .the feeding means asynchronously tothe speed of the knives.

2.I 'I'he combination of la leveller, a rotary shear in tandem relationthereto, and having cutting knives adapted to make transverse cuts onstrip material fed to it by the leveller, a pair of variable speed pinchrolls for feeding the material .to the cutting knives. and means forforming and maintaining a, loop in the material between the ylevellerand the said pinch rolls, the said loop being automatically controlledby variations in speed of the leveller.

3. In a rotary shear for making transverse cuts on moving material inthe form of a strip, a pair of rotary knife carrying drums mounted oniixed centers and gearedtogether, cutting knives carried thereby, a pairof pinchrolls each provided wi'th one or more pneumatic rubber tires for'contacting the strip and feeding the same to the knives, and means forvarying the working radius of .the said pneumatic tires to vary thelength of the strip so fed.

4. In a rotary shear for making transverse cuts on moving material inthe form of a strip, a

pair of rotary knife carrying drums mounted on iixed centers and gearedtogether, cutting knives carried thereby, a pair of pinch rolls eachprovided with one or more pneumatic rubber tires for contacting thestrip Aand .feeding the same to tl'ie knives, and means for varying theworking radius Aoi.' Ithe said tires to varythe length of strip so fed,comprising a screw down mechanism which may be operated to bring thepinch rolls closer to, or further from each other.

5. In a rotary shear for making transverse cuts on moving material inthe form ofa strip, a pairl of rotary knife carrying drums mounted oniixed centers and geared together, cutting knives carried thereby, apair of pinch rolls each provided with one orl more pneumatic rubbertires for contacting ,the strip and feeding the same to the knives,means for varying the working radius of the said .tires to vary thelength of the strip so fed, in combination with a set of selective gearsfor varying the speed of the pinch rolls. L

6. In a rotary shear for making transverse cuts on moving ,material inthe form of a strip,` a pair of rotary knife carrying drums mounted onfixed centers and geared together, cutting knives carried thereby. apair of pinch rolls for feeding .thematerial to the knives, ,and a gearbox containing four shafts, the iirst'shaft being driven at the samespeed as the knife carrying drums, and the second shaft being drivenfrom p a pair of rotary knife carrying drums mounted` on ixed centersand geared together, cutting knives carried thereby, a gear boxcontaining selectively operated gears, a pair of final shafts inytflrefsaid gear box, a pair'of pinch rolls for feeding the material tothe cutting knives, and a spindle connecting each of the said nal shaftsVwith one of the saidpinch'rolls to permit of bodily adjustment of thelatter.

' 8. In a rotary shear for making transverse cuts on moving material inthe form of a strip, a pair of rotary knife carrying drums mounted onfixed centers and geared together, cutting knives carried thereby, agear box containing selectively operated gears, a pair of hollow shaftsin the said gear box, a pair of pinch rolls for feeding the material .to.the cutting knives, the said pinch rolls each being mounted on a hollowshat, and

, a spindle connecting each of .the hollow shafts in the gear box withone of the said hollow pinch roll shafts, the said spindle having mostof its length within the said two hollow shafts.

9. In a rotary shear for making transverse cuts on moving material inthe form of a strip, a pair of rotary knife carrying drums mounted onfixed centers and geared together,`cutting knives carried thereby, aseries of small rollers adjacent to the knife drums and belowthepdelivery point of the knives, a shaft driven from one of the saidknife drums, and frictional driving connections between vthe s'aid shaftand the said rollers.

10. The combination with a leveller, of a' rotary shear arranged toreceive the material as fed to it by the leveller, and cut ittransversely into desired length sections, means for starting a loop inIthe material between the leveller and the shear comprising a descendingguide or chute to receive the material from the leveller, an inclinedbel-t conveyor for receiving the front end of the strip from the saidchute and carrying it to the shear, and means for automaticallymaintaining the said loop when formed.

Y 11. In a rotary shear for making transverse cuts on moving material inthe form of a strip, a pair of rotary knife carrying drums mounted -onfixed centers and geared together, cutting knives carried thereby, abelt conveyor arranged to receive the cut sections as discharged by thecutting knives, and an intermittently opemtable drive for the saidconveyor, whereby the belt may be stopped to allow the cut sections toform a pile thereon, and then started to convey the said pile to adesired point of discharge.

I.12. In a rotary shear for making transverse cuts on moving material inthe form of a strip, a, pair of rotary knife carrying drums mounted onfixed centers and geared together, cutting knives carried thereby, apair of pinch rolls for feeding the strip to the cutting knives, a gearbox for driving the pinch rolls at variable speeds to vary the rate ofstrip feed, an elevated oil reservoir, and an oil pump within the gearbox and driven by one of its shafts to keep the said reservoir suppliedwith oil, from whence it may be fed by gravity to point-s requiringlubrication.

13. In a rotary shear for making transverse cuts on moving material inthe form of a strip, a pair of rotary knife carrying drums mounted onfixed centers and geared together, cutting knives carried thereby, andmeans for feeding the strip to the cutting knives comprising thecombination of pinch rolls, speed varying gears to drive the same, Ithesaid pinch rolls having continuous unbroken outer driving surfaces forall adjusted radii, and means' for varying the radii of the said pinchrolls by smaliamounts so as to .produce cut sections varying in lengthby a few thousandths of an inch.

14. The method of operating a rotary shear having a plurality of pairsof rigidly attached coacting shear knives, consisting in feeding thematerial to be cut to the knives with a degree oi' asynchronismproportioned to the numberof pairs of knives in use, in order to cutoffsections of desired length. A

15. The method of operating a rotary shear having two or more co-actingpairs of detachable shear knives, to cut olf sections of desired lengthfrom amoving strip, comprising the use of a single pair, or a pluralityof pairs, of knives, feeding the strip to the knives with a degree ofasynchronism to produce the cut lengths desired, and rotating the knivesat a speed in proportion tocthe degree of asynchronism used.

WALTER W. MAOFARREN.

